If you want to modify the existing CHDK sources to build your own version, you need:
- Knowledge of the programming language C. (online tutorials and resources)
- A simple text editor to modify the source code or an advanced texteditor with syntax highlighting (for example Notepad++) or a C development environment.
- The source code (How to get it).
- Instructions how to compile the CHDK, which can be found here: Linux, Windows and Mac OS X.
- A SVN-client may be useful if you want to participate in the CHDK development or if you want to keep your own version always up-to-date (see here).
The procedure itself is pretty straightforward: Try to figure out what the source code does, apply modifications as you see fit, compile it and test it on your camera.
Don't be afraid to change anything! From a safety point of view you can modify any files. There is no code in the sources which allows to update (rewrite) the original firmware (read here). So, the worst thing which can happen is just that the new code wont work. If that happens, turn off the cam or remove the batteries, and everything should be fine again.
Source Guide Edit
The Source Code in the assembla subversion repository.
CHDK source was split into two main streams effective Dec 26,2011. A stable stream was created as a branch and the main trunk became the development or unstable stream.
SVN Link : Stable branch
SVN Link : Development trunk
trunk - This is where the latest CHDK development version is built from. It likely contains code that is unstable and not well tested. It is NOT the source for the stable versions available from the CHDK autobuild server.
- bin - Binaries. Normally empty. You will find your binaries here after compiling the source.
- CHDK - Files intended for CHDK directory on the SD card.
- core - The core of the CHDK. If you like to add something or modify the existing functionality, this is probably the only folder you need to look into. (Maybe also 'lib' and 'include'.)
- doc - Documentations. Not necessarily needed for compiling your own version.
- fonts - Fonts. Not needed for compiling your own version.
- include - Header files. Also see 'core'.
- lib - Libraries: some math and standard C functions, uBASIC, fonts, other "separate" stuff. Also see 'core'.
- loader - Initial code ran by camera. Sets up various things. No need to modify anything here (except perhaps if you want to port the CHDK onto a new camera model).
- platform - Camera-/Firmware-dependent code. You only need to modify anything here if you want to add new references to functions of the original firmware.
- platform/generic - Camera-/Firmware-independent code. You only need to modify anything here if you want to add new references to functions of the original firmware.
- script - Example scripts. Not needed for compiling your own version.
- tools - Tools to make life easier :). You only need to modify anything here if you want to add new references to functions of the original firmware.
branches - Branches are used for both stable version(s) of the CHDK tree and for special development versions.
- release-1_0 - the stable branch as of Dec 26, 2011. This branch holds the latest stable release available from the CHDK autobuild server. The only changes made to this branch are bug fixes and the addition of new cameras as they are ports.
- There are also a few older branches in there worth mentioning. Note that all of these branches are abandoned and discontinued now.
- dataghost - DataGhost's experimental branch with LOTS of nice things he found out (mainly about the s5is) - see here
- grand - grAnds original branch
- juciphox - a quite new branch created by Jucifer and PhyrePhoX which then later was merged into the main CHDK
- old-trunk - well, the old trunk - before the merging of JuciPhoX
- vitalyb - backup of the original branch by the founder of CHDK - vitalyb
- Read more about it here.